Display modules for displaying information are attached to apparatus housings in various fields.
For example, a communication apparatus connected to optical fiber cables is equipped with a display module that displays by the illumination of an LED the wavelength of the optical signal being transmitted through the optical fiber.
FIG. 1 shows an example of a communication apparatus connected to optical fibers.
A communication apparatus 10 described here is housed in the apparatus housing 11, and a plurality of optical cables 13 for transmission of optical signals is connected to the apparatus 10. A display module 14 is disposed on the optical cables 13 at its root on a side of the apparatus housing 11. The display module 14 includes a plurality of LED segments disposed in an array for displaying the wavelength of an optical signal transmitted through the optical cables 13. The optical cables 13 may be moved upward or downward to a certain extent, and the freely rotatable display module 14 is supported by the apparatus housing 11 so as not to hinder the movement of the optical cables 13.
FIG. 2 is an exploded perspective view of the display module shown in FIG. 1.
The display module 14 includes a display unit 15 and a housing 16 for the display unit. The display unit 15 includes a display screen 151 having the LED segments disposed in an array, a drive circuit (not shown) for driving the display screen 151, and a connector 152 for connecting the display unit 15 to an external part. A double-coated adhesive tape 153 is applied on either side of the display screen 151 to attach the display unit to the display unit housing 16.
The display unit housing 16 has a front cover 161 for covering the front of the display unit 15 and a pair of side covers 162 for covering the sides of the display unit 15. The front cover 161 includes: a window 161a for inspection of the display screen formed in the part corresponding to the display screen 151 of the display unit 15; and two slits 161b formed above the window. A label 164 is attached to the front of the front cover 161 so as not to cover the slits 161b and the window 161a for inspection of the display screen. In addition, a pair of side covers 162 are installed by shafts 163 projecting outwards from both of the side covers 162. The shafts 163 are formed integrally with the side covers 162. The shafts 163 are fitted into a pair of supporting holes in the apparatus housing 11 shown in FIG. 1 so as to be freely rotatable.
FIG. 3 shows a method for attaching the display module to the apparatus housing.
FIG. 3 shows the housing 16 for the display unit as viewed from above, and a horizontal cross section of the apparatus housing 11.
The apparatus housing 11 has a pair of supporting holes 111 into which the shafts 163 of the housing 16 for display unit are fitted such that the housing 16 is supported by the apparatus housing 11 so as to be freely rotatable around the shafts 163.
To fit the shafts 163 into the supporting holes 111, it is preferable to make the portions equipped with the shafts 163, of the side covers 162 of the housing 16 for display unit, resilient in the directions indicated by the arrows A. With the portions of the side covers 162 resilient as such, the shafts 163 are fitted into the supporting holes 111 in the directions indicated by the arrows B. The pair of slits 161b in the front cover 161 of the housing 16 for the display module is formed so as to facilitate the resilient bending of the portions of the side covers 162 on which the shafts 163 are formed.
Although the display unit 15 is not shown here, the display module 14, with the display unit 15 affixed to the housing 16 with the double coated adhesive tapes 153, is supported by the apparatus housing 11 so as to be freely rotatable around the shafts 163.
A display module having the foregoing structure has suffered from the problems described below.
(1) During ESD (Electrostatic Discharge) tests, the discharge energy is transmitted directly to the display unit 15 via the slits 162 and the window 16 for inspection of the display screen, damaging the display unit 15.
(2) Pieces of double-coated adhesive tape 153 are used to attach the display unit 15 to the housing 16 for display unit, which is a time consuming process. In particular, if the display screen 151 is attached to the housing 16 at an angle, the pieces of tape must be peeled off and replaced with new ones, wasting many man-hours.
(3) When a product is disposed of, for recycling, the product has to be disassembled and the components have to be categorized. Because the conventional structures use pieces of double-coated adhesive tape to affix the display unit, disassembly requires many man-hours unless the person who does this task is knowledgeable about the holding structure of the display unit of the display module. Simply detaching the double-coated tape alone takes much time.
As a preventive measure against the ESD problems described above, Japanese Patent Application Laid-Open No. 11-251761 (patent document 1) employs a film sheet for covering display parts, such as an LED mounted on a printed circuit board.
However, a thin film sheet does not offer sufficient protection against ESD, while covering the display part with a thick film is unacceptable in view of structure.
Japanese Utility Model Application Publication No. 6-33502 discloses an illumination display device constituting a unit display for a group of display panels. The illumination display device has a plurality of members disposed in front of the LEDs, making the structure intricate. This may be effective in preventing the ESD problems. However, nothing is mentioned about the ESD problem in the above document. Furthermore, the intricate structure of the display device would make it too costly to employ.